It is desirable to mold polyethylene terephthalate resins to obtain molded articles that are well crystallized and have smooth, glossy surfaces. One way to obtain such articles is to use very high mold temperatures, e.g., above 130.degree. C. Another way is use a crystallization-rate-increasing system, such as is described in published British application No. 2,015,014A. However, new systems for improving the crystallization rate of polyethylene terephthalate molding resins are continually being sought.
Moreover, with most polyethylene terephthalate molding resins, difficulties are encountered when articles molded from the resins are removed from the mold. Specifically, the articles tend to stick in the mold. This sticking problem is most apparent when thin, high surface area articles are molded. Because of their thinness, the effort (as exerted by knock out pins) required to remove the article from the mold can badly deform the article. An additive to reduce such sticking tendencies, i.e., a mold release agent, is desirable; however, the additive should not decrease strength properties, such as impact strength.